A known tandem image forming apparatus is provided with image carriers corresponding to yellow, magenta, cyan and black toner. Such a tandem image forming apparatus can print in color at substantially the same speed as printing in monochrome, because a toner image of each color is formed at substantially the same time on each corresponding one of the image carriers and each of the different colored images is sequentially laid on top of a sheet while the sheet passes the image carriers.
As disclosed in one example of this type of tandem image forming apparatus, an image carrier cartridge supports image carriers, each associated with one color. The image carrier cartridge is slidably installed in or removed from a body casing of the image forming apparatus. A developing cartridge for developing an electrostatic latent image formed on each of the image carriers is removably set in the image carrier cartridge.
In one example of an image forming apparatus, four developing cartridges are installed in a frame of the image carrier cartridge with little space. Therefore, it is not easy to install in or remove the developing cartridges from the image carrier cartridge.